The present invention generally relates to the field of software distribution in a digital computer network and, more specifically, to a method and system for remote distribution and installation of digital computer programs from a source data processing system to at least one target data processing system, wherein the computer programs, in particular, are transferred as packages that are specified in a package list.
A method and system for the distribution of software and data in a digital computer network is disclosed in U.S. Pat. No. 5,845,090. The software and data are combined into single entities referred to as “packages”. Software packages are stored in a central package archive and a transfer program accesses the central package archive to schedule transfers of one or more software packages. The transfer program enables a user to specify, besides other attributes, the date and time for the transmission and the installation of the packages. Once a software package is scheduled for transmission to a target computer, an indication is stored in an outbound package queue. A package transfer agent program acts on this indication and transfers the package from the central package archive to the target system. A corresponding package transfer agent on the target system places packages in an inbound package queue. Finally a transfer daemon determines the package type and acts accordingly. If the package type is ‘Distribution’, then it messages the package to start installation.
Further, known software distribution/installation approaches like the IBM Tivoli Software Distribution product have in general two concepts for bringing software from a software repository to a particular target computer system. These concepts are called ‘Push’-Mode and ‘Pull’-Mode distribution.
A Push-Mode distribution is initiated by an operator or an automated process from a central point, aiming to force a software installation on all reachable target systems of a desired range. The Push-Mode distribution has disadvantages in large computer environments, especially environments spread over several continents, where the number of reachable target systems may be rather small. This is due to the fact that a standard end-user workstation may be online less then twelve hours a day and there is a lot of planning overhead to make sure a set of targets is online, at the very time the distribution will take place. Time zones, working hours and holidays have to be considered, and often, a software installation is not welcome during office hours. The last fact is not really a problem for server systems, which are generally up 24 hours a day but again for end-user systems, where either the users have to be forced to leave their machines up after work or to wake the systems up by hardware features such as Wake-On-LAN, which may not be available for all target systems in scope.
In contrast to the aforedescribed Push-Mode distribution, a Pull-Mode distribution is initated by a user of a target computer system or the target system itself. The activation of the installation may be initiated in a quiet mode, i.e. automatically during a system or user logon, without user attendence, or by a user interface giving a list of available packages to select from for installation.
The Pull-Mode distribution technique has the advantage over the predescribed Push-Mode technique that the target system is already online when the distribution is started.
But the drawback of the PULL-Mode distribution is that an exact time for the distribution/installation can not be determined in advance. This may result in target systems which are not updated in time since it is not forseeable at which time a login of the target system is performed.
In addition, a peak load in the distribution and network environment on the side of the source system, e.g. when a large number of users is logging into their systems, will cause time delays for starting a distribution/installation or cause a decrease in the overall throughput and thus will drop distribution/installation performance.